荞麦主要拒Na^＋部位及其Na^＋／H^＋逆向转运活性的研究

Study on Main Na^+ Exclusion Localization and Na^+/H^+ Antiport Activity of Buckwheat

【目的】确定荞麦(Fagopyrum esculentum Moench)的主要拒Na+部位、质子泵和Na+/H+逆向转运活性与其拒Na+特性的关系。【方法】以耐盐荞麦品种川荞1号和盐敏感荞麦品种TQ-0808为试验材料,采用"压力室"法压取木质部汁液,测定各部位拒Na+能力;采用蔗糖密度梯度离心法分离细胞质膜和液泡膜,测定质子泵和Na+/H+逆向转运活性。【结果】盐敏感品种的主要拒Na+部位在根部,耐盐品种的主要拒Na+部位在根部和茎基部,耐盐品种整体拒Na+能力明显大于盐敏感品种;相同盐浓度处理下,耐盐品种质子泵和Na+/H+逆向转运活性明显大于盐敏感品种,说明耐盐品种主要拒Na+部位细胞的排Na+能力和Na+区隔化能力明显大于盐敏感品种。【结论】耐盐品种主要拒Na+部位Na+的区隔化在限制Na+向地上部运输中发挥了重要作用,是耐盐荞麦品种主要拒Na+部位拒Na+的主要方式。

[Objective] The objective of this experiment is to determine the main Na^＋ exclusion localization of buckwheat （Fagopyrum esculentum Moench） and the correlation between proton pump and Na^＋/H^＋ antiport activity with Na^＋ exclusion property. [Method] Buckwheat varieties Chuanqiao 1 （salt-tolerant variety） and TQ-0808 （salt-sensitive variety） were used as experimental materials. Na^＋ exclusion capability of different parts was determined through ＂pressure chamber＂ method extruding xylem juice. Proton pump and Na^＋/H^＋ antiport activity were also determined by sucrose density gradient centrifugation method separating plasmolemma and tonoplast. [Result] The main Na^＋ exclusion localization of salt-sensitive variety was in roots, while that of salt-tolerant one was in roots and stem base, and the whole Na^＋ exclusion capability of salt-tolerant variety was obviously higher than that of salt-sensitive one. Proton pump and Na^＋/H^＋ antiport activity of salt-tolerant variety were obviously higher than that of salt-sensitive one in the same salinity treatment. It indicated that Na^＋ extrusion capability and Na＋ circumscription capability of the main Na^＋ exclusion localization cell in salt-tolerant variety were obviously higher than that in salt-sensitive one. [ Conclusion ]Na^＋ circumscription of the main Na^＋ exclusion localization in salt-tolerant variety played an important role in restricting transportation Na^＋ to shoot, which was the main way to Na exclusion of main Na^＋ exclusion localization in salt-tolerant buckwheat variety.